反应详情

To 2-bromo-5,6-dichloro-1-(2,3,4-tri-O-acetyl-beta-D-xylopyranosyl)-1H-benzimidazole (0.083 g, 0.16 mmol) magnetically stirring in 7 ml of tetrahydrofuran was added sodium carbonate (0.13 g, 1.2 mmol) in 1 ml of water. The mixture was allowed to stir at rt for 7 days, then heated at reflux for 2 h. The mixture was cooled to rt, neutralized with acetic acid (0.059 ml, 1.0 mmol) and stirred for an additional 0.5 h at rt. The product, 2-Bromo-5,6-dichloro-1-beta-D-xylopyranosyl-1H-benzimidazole, was purified on a silica gel column (2.5×10 cm, 230-400 mesh) eluting with ethyl acetate (0.40 g, 0.10 mmol, 63%); m.p. 149.6° C. (decomposes); 1H NMR (DMSO-d6) δ7.95 (s,1H), 7.90-7.80 (bs, 1H), 5.48-5.46 (d, J=5.2 Hz), 5.40-5.30 (bs, 1H), 5.23-5.19 (m, 2H), 3.96-3.90 (m, 1H), 3.85-3.50 (2 overlapping bs, 2H), 3.43-3.20 (m, 2H obscured by HOD peak).

1. temperatureheated
2. temperatureat reflux for 2 h
3. temperatureThe mixture was cooled to rt
4. stirringstirred for an additional 0.5 h at rt
5. customThe product, 2-Bromo-5,6-dichloro-1-beta-D-xylopyranosyl-1H-benzimidazole, was purified on a silica gel column (2.5×10 cm, 230-400 mesh)